1. Field of the Invention
The present invention is directed to a nacelle anti-icing system for a jet engine and in particular to an anti-icing system wherein a heated gas boundary layer is formed along the inlet duct and bullet of the jet engine so as to prevent icing.
2. Description of the Prior Art
It is conventional in anti-icing systems to provide a nose cowling assembly 1 shown in FIG. 1 which includes an air feed duct 2 for feeding air heated to 350.degree. such that such heated air is in communication with conduit 4 so as to heat the adjacent skin layer of the noise cowling and prevent freezing of runback moisture. Also shown in FIG. 1 is the bullet 6 which is positioned radially within nose cowling assembly 1.
A drawback of the prior art shown in FIG. 1 is that conduit 4 must be provided along the inner surface of the nose cowling assembly which is complex in construction and prevents the use of any noise abatement material in that such prevents installation of any acoustical material within the nose cowling for minimizing the noise generated by the engine. In addition, means are required for feeding of heated air at a sufficiently high temperature of 350.degree. wherein air heated to such extreme temperature must be provided through a complex construction of conduit 4 which thus leads to a complicated total structure for the nose cowling assembly 1 in the conventional jet engine.